Lénárt R. & Hók J., 2013: Polyphase deformation of the cover sequence and granitic rocks of the Zobor part of the Tribeč Mts.. Acta Geologica Slovaca, 5, 1, 107–115. (in Slovak with English summary)

Polyfázová deformácia obalovej sekvencie a granitoidov zoborskej časti Tribeča

Polyphase deformation of the cover sequence and granitic rocks of the Zobor part of the Tribeč Mts.

Rudolf Lénárt & Jozef Hók

Katedra geológie a paleontológie, Prírodovedecká fakulta, Univerzita Komenského v Bratislave, Mlynská dolina G, 842 15 Bratislava

Abstract

The Tribeč Mts. is a significant morphostructure of crystalline basement protruding from beneath Mesozoic and Neogene sediments. With respect to geological composition is divided into two parts. The Rázdiel part is situated on northeast side and comprises the Tatricum, Veporicum, and Hronicum tectonic units. The Tatricum and Fatricum units are presented in the Zobor part which is located on southwest. Kinematics and tectonic evolution of the Tatricum tectonic unit were the objects of study in the Zobor part of the Tribeč Mts. The Tatricum unit contains cover sedimentary sequence in stratigraphic range from the Early Triassic to Early Cretaceous. The crystalline basement comprises granitic rocks affected by mylonitization. Four main tectonic events took place since the Cretaceous to the Neogene. The first phase of ductile deformation (Late Cretaceous) is characterized by mylonitization of granitic rocks, folding and thrusting of the cover sequence with the sense of movement top to the NW. During the second phase (Cretaceous/Paleogene) steep mylonitic/shear zones within the granitic rocks were generated in a sinistral transpression with semi-ductile to ductile conditions. The third phase (Palaeogene) is characterized by tectonic unroofing which was realized on normal listric faults in semi-brittle conditions. In the final phase of the deformation evolution (Neogene) were generated normal faults separating the Tribeč horst structure against to Neogene depressions.

Key words: Western Carpathians, Tribeč Mts., thrusting, transpression, tectonic unroofing, ductile deformation, brittle deformation

Manuscript received: 2013-03-11

Revised version accepted: 2013-05-02